I wouldn’t call it weird. But it’s unenforceable.
This kind of thing works better with GPL. General use falls under GPL. If that doesn’t suit your commercial use, contact the copyright holder for another license.
As it stands, I can use the MIT licensed project anyway I like, including handing it to a commercial entity for their use.
It's no more unenforceable than GPL is unenforceable.
But MIT + weird condition is radioactive to anyone who takes licensing seriously.
Might just as well write "for hobbyist use only".
What's unenforceable? The non-commercial clause or the commercial clause? It's a contradiction.
The intent is not at all clear.
Does the author not mind people making money so long as they give back to the community? If so, then copyleft with exceptions by the license holder could be a compromise.
Does the author not want people making money at all without explicit permission? Then no open-source license will suffice and it should have been put under a non-commercial license or left without a license at all so that the default copyright restrictions apply.
You say that this project is MIT licensed and therefore available for you to use commercially. Is this true? The license section in the README clearly says not to use it for commercial purposes. Which takes precedence?